Risk assessment of antimony, barium, beryllium, boron, bromine, lithium, nickel, strontium, thallium and uranium concentrations in the New Zealand diet.

Identifying and monitoring dietary toxicants is an important component of contemporary food safety systems. To characterise their potential dietary risks, analysis was undertaken of 10 elements: antimony, barium, beryllium, boron, bromine, lithium, nickel, strontium, thallium and uranium in 132 different food types. All 10 elements were reported as quantified in aportion of the analysed foods, with prevalence ranging from less than 1% for antimony to 98% for barium. Dietary exposure assessment was undertaken for 10 New Zealand population cohorts using apublished simulated diet, and proportionality of food groups to total exposure identified. Characterisation against health-based guidance values identified no dietary risk from exposures to beryllium, boron, bromine, lithium, strontium and uranium to any of the population cohorts. For antimony and thallium, the exposure range for infants was calculated to exceed the health-based guidance value, and for barium and nickel, all mean exposures were above the health-based guidance value for younger population cohorts. Although some conservatism in applying upper-bound mean exposures reduces the likelihood of asignificant dietary risk, further laboratory method development and analysis of these elements in the New Zealand diet would be beneficial to ensure protection of New Zealand public health.

Inorganic arsenic in rice and rice products in New Zealand and Australia.

A total of 200 rice and rice products from New Zealand and Australia were purchased from retail outlets during 2017 for inorganic arsenic analysis by ICP-MS. The survey of foods placed a particular emphasis on products marketed specifically for infants and young. A total of 159 samples (80%) gave positive results for inorganic arsenic, with a mean concentration of 0.06 mg/kg and a range of <0.01-0.14 mg/kg. Two products marketed for infants and young children age-cohort had the highest concentrations of inorganic arsenic. Both exceeded the EU maximum level for rice destined for the production of food for infants and young children of 0.1 mg/kg. The mean concentration of inorganic arsenic for only raw rice samples was 0.07 mg/kg, with a range of <0.02-0.12 mg/kg. In general, the concentration of inorganic arsenic in rice and rice products from New Zealand and Australia was low compared to concentrations reported from comparable studies overseas.

Analysis and Assessment of Exposure to Selected Phthalates Found in Children's Toys in Christchurch, New Zealand.

Internationally several phthalates are subject to regulatory control regarding maximum allowable concentrations in children's toys. Such regulation is not in place in New Zealand. Phthalates have been associated with developmental toxicity and endocrine disruption. We determined the concentration of seven phthalates in children's toys purchased in Christchurch, New Zealand. These results provided data for an exposure assessment deriving Hazard Indices (HI) for oral and dermal exposure routes in children, based on the concentration of mixtures of phthalates shown by the EU to produce either reproductive/developmental or hepatotoxic effects. Of the 49 toys analyzed, 65% contained at least one phthalate at a concentration of >0.1% by mass; and 35% contained multiple-phthalates at individual concentrations of >0.1%. A HI of 3.4 was derived for the combined exposures to the four phthalates associated with reproductive and developmental effects. A HI of 0.3 was derived for the group of phthalates associated with hepatotoxic effects. Five phthalates were detected at levels exceeding the EU regulatory limit of 0.1% by mass. Risk assessment calculations indicate that, using realistic exposure scenarios, the worst-case combined exposure to phthalates associated with developmental toxicity exceeded a HI of 1 so may cause adverse developmental effects.

Gold-gold junction electrodes:the disconnection method.

The formation of gold-gold junction electrodes for application in electroanalysis is described here based on electro-deposition from a non-cyanide gold plating bath. Converging growth of two hemispherical gold deposits on two adjacent platinum microelectrodes (both 100 µm diameter in glass, ca. 45 µm gap) followed by careful etching in aqueous chloride solution was employed. During growth both gold hemispheres "connect" and during etching "disconnection" is evident in a drop in current. Gold-gold junctions with sub-micron gaps are formed and applied for the electroanalytical detection of sub-micromolar concentrations of hydroquinone in 0.1 M phosphate buffer pH 7 (E(rev) = 0.04 V vs. SCE) and sub-micromolar concentration of dopamine in 0.1 M phosphate buffer pH 7 (E(rev) = 0.14 V vs. SCE). The potential future uses in analysis and limitations of gold-gold junction electrodes are discussed.